Citation
Kamaruddin, Fatin Amirah
(2021)
Fabrication of strengthening treatment method for marine clay.
Doctoral thesis, Universiti Putra Malaysia.
Abstract
Development of road traffic on marine clay poses a serious problem when
this type of soil is being used. In order to solve the problem, the soil would
need to be treated to improve its condition. Lime and alkaline activation (AA)
are binder techniques that can be used to improve soil strength. However,
treating soil with only binder would lead to brittle failure for the soil treatment.
Therefore, to improve the mechanical properties of the treated soils to
ductile, the inclusion of treated natural coir fibre with randomly distributed soil
reinforcement is required.
This research is focused on investigating the performance of treated coir
fibre with two different stabilizers by using lime and alkaline activation
subjected to static and dynamic loading. The surface of the fibre was treated
with calcium chloride (CaCl2), which was proven effective in increasing the
tensile strength and improving the fibre adhesion. For the laboratory work,
165 samples (for main tests-range of 3 duplicate tests each) were tested
according to the British Standard (BS) and American Society for Testing and
Materials (ASTM). The specimens were prepared by using the remoulded
method and were cured for 7, 28 and 90 day curing periods before the testing
was conducted. There were seven major tests carried out on untreated soils,
treated soil with lime, and treated soil with alkaline activation, which were
physical properties, compaction test, unconfined compressive strength
(UCS) test, flexural strength (FS) test, indirect tensile strength test (ITS),
consolidated isotropic undrained (CIU) test (static load), and dynamic loading
test. For the determination of soil behaviour on the CIU test, two types of
parameters, which are maximum deviator stress and axial strain, were
obtained and analyzed. The results were then used for the further
investigation in the dynamic loading test. Besides that, for fundamental
research on dynamic loading, the main parameters were comprised of the
damping ratio (D) and shear modulus (G). The parameters were defined
based on the equation from the stress-strain curve that is generated through
AutoCAD software to calculate the area that is produced by the hysteresis
loop.
The results of this study show that for a 7 day curing period up to a 90 day
curing period, the compressive strength, flexural strength, and indirect tensile
strength tests of treated soil with alkaline activation showed higher
increments than treated soil with lime. The increments observed were up to
46 % and 71 % for the unconfined compressive strength test, 35 % and 81
% for flexural strength, and 53 % and 69 % for the indirect tensile strength
test for both treated lime and alkaline activation, respectively. Other than
that, the strength of the increment can be summarized up to 87 % and 98 %
for both treated with lime and alkaline activation compared to the untreated
soil specimens for the three tests. Moreover, for the dynamic loading test, it
can be concluded that the value of G was increased with the addition of
stabilizer in the soil, which can be interpreted by the decrease of strength as
the curing periods increase between 60 to 40 kPa (lime) and 760 kPa to 210
kPa (AA). Meanwhile, for the value of D, the result showed a decrease as
the curing periods increase from 23 % to 32 %, 15 % to 25 % and 5 % to 9
% for untreated soil, treated soil with lime, and treated soil with alkaline
activation, respectively. These results show that the addition of the stabilizer
to the soil had different effects on the dynamic loading parameter behaviour.
The test can be confirmed with the field emission scanning electron
microscopy (FESEM) and energy-dispersive X-ray spectroscopy (EDX) tests
where there is an interaction between treated soil and fibre as filler, thus
strengthening the soil. Therefore, it can be concluded that this research is
important as it contributes to proving that the inclusion of fibre as one of the
admixtures in the stabilizer not only helps in improving the mechanical
interactions between the soil, fibre and the stabilizer but it also results in
increasing the performance of the soils as it could be used for the
development of light traffic loading in the area of marine clay.
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